Identification of parental chromosomes, intra-chromosomal changes and relationship of the artificial intergeneric hybrid between Chrysanthemum horaimontanum and Tanacetum vulgare by single color and simultaneous bicolor of FISH and GISH

Abstract

The maternal Chrysanthemum horaimontanum (2n=18) and the paternal Tanacetum vulgare (2n=18) were artificially crossed and produced hybrid strains which were raised by embryo rescued and axenic cultured in vitro and later acclimatized in vivo. The hybrid plants had the chromosome number of 2n=18, 19 and 27. The technique of genomic in situ hybridization (GISH) made it possible to distinguish between the two parental genomes in the chromosome complement of the F₁ hybrid plants. Some of the hybrid plants showed genome rearrangement as a translocation in certain somatic chromosomes of C. horaimontanum and T. vulgare. Parental chromosomes that carried the 45S rDNA could be marked by simultaneous bicolor hybridization using the digoxigenin labelled total genomic DNA of T. vulgare probe and the biotin labeled pTa71 probe. A signal of 45S rDNA was hybridized in the nine chromosomes of C. horaimontanum, while three signals were hybridized in the nine chromosomes of T. vulgare in the chromosome complement of their F₁ hybrid.